Geotechnical data collection and application to the Leeville underground mine

Transactions of the Society for Mining, Metallurgy, and Exploration , 2010, Vol. 328, No. 1, pp. 420-428

Sun, Changshou

The Leeville underground mine has been in operation since 2006 and currently produces 3,175 t (3,500 st) of ore per day with an average gold grade of 12.6 g/t (0.4 opst). The mine has a large horizontal extent of 762 by 152 m (2,500 by 500 ft) and a vertical extent of 6 to 61 m (20 to 200 ft). Based on the characteristics of the ore bodies, the deposits are divided into several mining zones. The geotechnical properties of mining zones are also different from one zone to another. A successful geotechnical collection system is very important for mining design and operation in the Leeville underground mine.

Three methods are used to collect the geotechnical data in the Leeville underground mine:

• Core logging. Most geotechnical data are collected by this method, which is based on exploratory drills and estimates parameters for rock quality designation (RQD), fracture frequency (FF), compressive strength and rock mass rate (RMR).
• Site investigation. This method collects more detailed geotechnical data and geostructural data from work done in the underground drifts and stopes. Parameters of RQD, FF, compressive strength, RMR, rock tunneling quality index (Q) and geostructural data are estimated.
• Data collected from drill holes made for the critical infrastructure facilities. This method provides the best detailed geotechnical information for areas in which the critical infrastructure located.

A complete geotechnical database has been constructed using this geotechnical data collection system. The database can be used for the design of ground support, stopes and stope blasts, among other critical applications.